A Beginner’s Guide to the Low FODMAP Diet
A diet low in certain fermentable carbohydrates, known as the low FODMAP diet, is sometimes recommended to help manage symptoms of irritable bowel syndrome (IBS) under professional guidance.
IBS is a common digestive condition in Australia, and many adults report uncomfortable symptoms.
For some people with IBS, food can be a trigger for symptoms such as abdominal pain and bloating.
Restricting certain foods may help reduce symptoms for some individuals. This is where the low FODMAP diet may be considered.
This article explains what the low FODMAP diet is, how it works, and who it may be suitable for.
What are FODMAPs?
“FODMAP” stands for “fermentable oligo-, di-, and monosaccharides and polyols”.
These are short chain carbohydrates that may be poorly absorbed in the small intestine for some people. They can draw water into the bowel and be fermented by gut bacteria, which can increase gas.
For some people, this process can contribute to digestive symptoms such as bloating, gas, abdominal pain, and changes in bowel habits, including constipation, diarrhoea, or both.
Some people with IBS report that these carbohydrates can trigger or worsen symptoms.
FODMAPs are found in varying amounts in a wide range of foods. Some foods contain one type, while others contain several. Primary dietary sources of the four groups of FODMAPs include:
- Oligosaccharides: wheat, rye, nuts, legumes, artichokes, garlic, and onion
- Disaccharides: lactose containing foods such as milk, yoghurt, soft cheese, ice cream, buttermilk, condensed milk, and whipped cream
- Monosaccharides: fructose containing foods including apples, pears, watermelon, mango and sweeteners such as honey, agave nectar, and high fructose corn syrup
- Polyols: mannitol and sorbitol in apples, pears, cauliflower, stone fruits, mushrooms, and snow peas, plus xylitol and isomalt found in some low calorie sweeteners such as sugar free gum and mints
FODMAPs are a group of fermentable carbohydrates that can aggravate gut symptoms in people who are sensitive to them. They are found in many everyday foods.
What foods can you eat on a low FODMAP diet?
Many foods are naturally low in FODMAPs, including a range of proteins, grains, fruit and vegetables.
While coffee and black and green teas are generally considered low FODMAP, caffeinated beverages may still trigger symptoms for some people with IBS, so limiting caffeine may be helpful for certain individuals.
It is also important to check ingredient lists on packaged foods, as manufacturers may add higher FODMAP ingredients for flavour, as prebiotics, as fat substitutes, or as low calorie sugar substitutes.
Many foods are naturally low in FODMAPs. When following a low FODMAP diet, pay close attention to packaged and processed foods, which may contain added FODMAP ingredients.
Benefits of a low FODMAP diet
A low FODMAP diet restricts high FODMAP foods. Evidence suggests this eating pattern may benefit some people with IBS when used correctly and for an appropriate duration.
May reduce digestive symptoms
IBS symptoms vary widely but may include abdominal pain, bloating, reflux, flatulence, and bowel urgency. These symptoms can significantly affect day to day comfort.
Research suggests a low FODMAP diet may help reduce symptoms such as stomach pain and bloating for some people with IBS. Individual results vary.
May improve quality of life
People with IBS often report reduced quality of life when symptoms are frequent or severe, including impacts on social life and work.
Some studies suggest that reducing symptom severity through dietary changes may also improve overall wellbeing, including energy and daily functioning, for some individuals.
Summary
Studies suggest a low FODMAP diet may reduce certain IBS symptoms and may improve quality of life for some people. Results vary, and it is not effective for everyone.
Who should follow a low FODMAP diet?
A low FODMAP diet is not suitable for everyone. Unless you have IBS or have been advised by a qualified clinician, it may be unnecessary and may have downsides.
This is because many FODMAPs act as prebiotics, supporting beneficial gut bacteria. Removing them long term may negatively affect gut microbiota.
In addition, restricting multiple fruits, vegetables, grains and dairy foods may reduce fibre intake and increase the risk of nutrient deficiencies if not properly planned, which may worsen constipation for some people.
To support nutritional adequacy and reduce the risk of imbalances, follow this approach only under the guidance of a dietitian experienced in digestive disorders, and ideally with medical assessment.
If you have IBS, you may consider discussing this dietary approach with a qualified health professional if you:
- have ongoing gut symptoms
- have not improved with stress management strategies
- have not improved with first line dietary strategies, such as adjusting meal size and frequency and limiting alcohol, caffeine, spicy foods, and other common triggers
There is discussion about possible use in other conditions such as diverticular disease or exercise related gut symptoms, but more research is needed.
Because the diet is structured and restrictive, it is usually best not to start it for the first time while travelling or during a particularly busy or stressful period.
Summary
A low FODMAP diet may help some adults with IBS, but it should be used with professional guidance and typically after simpler dietary strategies have been tried.
How to follow a low FODMAP diet
A low FODMAP diet is a structured approach that usually involves three stages.
Stage 1: Restriction
This stage involves temporarily reducing or avoiding high FODMAP foods.
This stage is not intended to be permanent. It commonly lasts around 4 to 8 weeks, depending on individual response and professional guidance.
Some people notice changes within the first week, while others may take several weeks to notice improvement.
If you achieve adequate relief of symptoms, you can progress to stage 2.
Stage 2: Reintroduction
This stage involves systematically reintroducing high FODMAP foods to identify which types and amounts trigger symptoms.
The duration varies, but it often takes several weeks.
In this phase you aim to:
- identify which FODMAP groups you tolerate, because not everyone reacts to all of them
- identify the amount you can tolerate, sometimes called your personal threshold
Typically, you test small amounts of a specific food for several days while keeping the rest of your diet low FODMAP. You then allow a short break before testing the next food to reduce overlap effects.
This step is best done with a dietitian who can guide appropriate testing and interpretation.
Unlike many food allergies where strict avoidance is necessary, some people with IBS can tolerate small amounts of certain FODMAPs.
Stage 3: Personalisation
This is sometimes called the modified low FODMAP diet. You continue to limit only the foods and amounts that trigger symptoms, and reintroduce foods that are well tolerated.
The goal is to increase variety and flexibility while maintaining symptom control. This stage is generally intended to be the long term approach.
Summary
The low FODMAP diet is a three stage process: restriction, reintroduction, and personalisation. Each stage plays a role in supporting symptom management and nutritional adequacy.
Three things to do before you get started
Follow these steps before starting a low FODMAP diet.
- Make sure you have IBS
Digestive symptoms can occur in many conditions, including conditions that require medical assessment.
Symptoms similar to IBS can occur with coeliac disease, inflammatory bowel disease, defecatory disorders, and bowel cancer.
A doctor can help rule out other causes and confirm whether IBS diagnostic criteria are met.
- Try lifestyle and first line dietary strategies
The low FODMAP diet can be time and resource intensive. It is often used when other strategies have not helped enough.
Examples include:
- regular physical activity
- reducing caffeine if it triggers symptoms
- eating smaller, regular meals
- stress reduction strategies, including psychological support when appropriate
- considering probiotics for some people, under professional advice
- limiting deep fried foods and very spicy foods if they trigger symptoms
- Plan ahead
The restrictions can be challenging at first. Planning can help.
- Find credible low FODMAP food lists and resources
- Remove or separate high FODMAP foods to reduce confusion
- Create a low FODMAP shopping list before shopping
- Review menus in advance when dining out
Summary
Medical assessment, first line strategies, and planning can improve your chance of following the low FODMAP approach safely and effectively.
Can vegetarians follow a low FODMAP diet?
A well planned vegetarian eating pattern can be low in FODMAPs, but it can be more challenging because some staple vegetarian proteins, such as legumes, can be high FODMAP in larger serves.
Some people can tolerate small portions of canned and well rinsed legumes, which may be lower in FODMAPs than larger serves of cooked legumes. Serve sizes matter.
Other low FODMAP protein options for vegetarians may include tempeh, tofu, eggs, quinoa, and many nuts and seeds, depending on individual tolerance.
Summary
Vegetarian low FODMAP eating is possible with planning and attention to serve sizes, ideally with dietitian support.
What if your symptoms do not improve?
The low FODMAP diet does not help everyone with IBS. Some people will not respond.
Before stopping, consider these common issues:
- Check and recheck ingredient lists
Packaged foods may contain hidden higher FODMAP ingredients such as onion, garlic, sorbitol, and xylitol, which can trigger symptoms in small amounts for some people.
- Use accurate FODMAP resources
Many food lists online are incomplete or inconsistent. Two widely recognised validated resources include:
- Consider other contributors
Diet is not the only factor affecting IBS. Stress, sleep, medication, hormonal changes, and other health conditions can also influence symptoms.
Talk with a doctor if you want to explore other evidence based options.
Summary
If symptoms do not improve, check for hidden ingredients, confirm your information sources, and consider other factors that may be contributing to symptoms.
The bottom line
A low FODMAP diet may improve digestive symptoms for some people with IBS, but it does not work for everyone.
It is a structured approach that includes restriction, reintroduction, and personalisation. It is not intended to be a one size fits all plan or a permanent strict elimination diet.
Because FODMAPs support gut bacteria and high FODMAP foods can be important sources of fibre, vitamins and minerals, this diet should generally be used only when needed and with professional guidance.
If you are looking for bulk billing in Cranbourne, please book an appointment with one of our doctors or GPs.
Risks and Recovery
This information is general in nature and is not a substitute for personalised medical advice. Digestive symptoms can be caused by a range of conditions, some of which require medical assessment. Do not self diagnose IBS.
Seek advice from a qualified health professional before starting this diet, especially if you are pregnant, breastfeeding, have diabetes, kidney disease, inflammatory bowel disease, coeliac disease, unexplained weight loss, rectal bleeding, fever, severe or persistent pain, or if you are taking medicines affected by diet.